Netscape Status codes

What I would like to do is set the Status of messages filtered
through procmail, but I am using Netscape mail, which tacks on the 
following header fields after email has arrived into the Inbox:

a) X-Mozilla-Status: xxxx
b) Content-Length: xxxx

I was wondering if anyone else has been doing such a thing using
Netscape mail and understood the codes for X-Mozilla-Status.

Thanks,
Greg